LTO tape storage, ranked by cost per terabyte

LTO (Linear Tape-Open) is magnetic tape engineered for long-term, large-scale archival, and on cost per terabyte of media it beats every other format on this site, often by a wide margin. The reason is structural: a cartridge is just a spool of tape and a chip — no motor, no circuit board, no platters — so the per-terabyte cost of the media itself is extraordinarily low, and a written tape can sit on a shelf for decades drawing zero power. That makes LTO the backbone of media archives, scientific data vaults, and the off-site ‘cold’ copy in serious backup strategies.

The catch is the drive. An LTO tape drive is a significant up-front investment, and tape is sequential — superb at streaming large files start-to-finish, poor at random access. So the economics only work at scale or for data you write once and rarely read: the more terabytes you archive per drive, the lower your true all-in cost per terabyte becomes. Each generation roughly doubles native capacity (LTO-9 holds 18 TB native, ~45 TB compressed) and drives typically read two generations back and write one back. When comparing cartridges, mind native vs compressed capacity (we rank on native), the generation your drive supports, and whether a listing is a single tape or a multi-pack.

LTO generations and compatibility

Each LTO generation increases capacity and speed. Drives are backward-compatible for reading and writing only across a limited window, so the cartridge generation must match what your drive supports. Capacities below are native; ‘compressed’ figures assume ideal 2.5:1 data and rarely apply to already-compressed media.

A modern LTO drive generally writes its own generation and reads one back; check the exact model before buying tapes. For the full economics — when a drive pays for itself and how to build an archive — read our LTO tape backup guide.